1. Field of the Invention
The present invention relates to a golf ball having a polyurethane cover, more particularly to a golf ball having a polycarbonate polyol-based thermoplastic polyurethane cover.
2. Description of the Related Art
As a base resin constituting a cover of a golf ball, an ionomer resin or a polyurethane is used. Covers containing ionomer resins are widely used for their excellent resilience, durability, workability and the like. However, because of their high rigidity and hardness, problems such as bad shot feeling, inadequate spin performance and poor controllability are pointed out. On the other hand, the polyurethane is used as a base resin constituting the cover since it provides an improved shot feeling and spin properties compared with an ionomer resin.
However, the abrasion-resistance of the cover containing the polyurethane is not at a satisfactory level, and its resilience is not necessarily adequate, either.
In order to solve the problem, as the base resin of the cover, the thermoplastic polyurethane containing the polycarbonate polyol as the constitutional component has been disclosed. Japanese patent publication No. 2,002-272,878 A discloses a golf ball having a core and a polyurethane cover covering the core wherein the polyurethane cover comprises a cured body obtained by curing a polyurethane prepolymer having a terminal isocyanate group with a curing agent. The polyol component constituting the urethane prepolymer is a polycarbonate having a number average molecular weight of 300 to 3000. U.S. Pat. No. 6,855,793 discloses a golf ball using polycarbonate-urethane as a constitutional element using poly(1,6-hexyl-1,2-ethylcarbonate) as a polycarbonate intermediate.